I am just spitballing here, but the price hike could very well be a precursor to the launch of the Star+ (Star Plus) Streaming service, that will start hosting a whole new array of content that are currently not hosted by Disney+. The new service will host more mature content (R-Rated movies, shows and other content targeted primarily toward adult audiences), as opposed to the primarily family oriented content of Disney+.
The service will be launched as a separate service/app called Star+, ONLY in Latin America. In other regions, the Star+ service will be integrated into the existing Disney+ service/app.
As for India, it will most likely be integrated into the existing "Disney+ Hotstar" app (now eventually owned by Disney), much like how all of the Disney+ content was integrated into the existing "Hotstar" app (then owned by Fox group, the then owner of the Star TV group) when Disney+ was launched. As we all know, the whole game changed when Disney bought much of the Fox network (including the 20th Century Fox studios, but excluding some properties like the Fox Television network, which includes the infamous Fox News channel) couple of years ago.
So, once Star+ comes to India, we might eventually end up with 3 hierarchical payment tiers inside of the Disney+ Hotstar app:
1) Disney+ Hotstar VIP
2) Disney+ Hotstar Premium
3) Disney+ Hotstar Star+
The Star+ service is expected to launch toward the end of this month (Feb 23, 2021) in most countries. It might take a while for it to launch in India (much like how they took time to integrate Disney+ into Hotstar).
So once that happens, we might as well see a price hike for Disney+ Hotstar Premium.
The imminent arrival of Star+, is the main reason why the "Star Plus" Hindi TV channel will be rebranded as "Utsav Plus", effective exactly a day (February 22, 2021) before the launch date of the Star+ service (February 23, 2021).
Star (Disney+) - Wikipedia
Star+ - Wikipedia